i can save so much money by not buying it... around $300, so how important is it really? wuld i be okay with the built in flash for a begginer? culdnt i liek put a peice of tissue in front of it to soften it?

It depends on what you want to do...and how much you care about how your flash photos look.

You can diffuse the built-in flash a bit...but it's the size of a flash that really makes it soft...so just a little tissue isn't going to make it all that soft. The big killer is that it's close to the lens...which means that the angle of light is not very inducive to good looking portraits etc. This is the cause of red-eye.

A hot-shoe flash is going to sit up higher and give you a better angle...but even that isn't good enough. This is why the 430 (and a lot of others) can tilt and rotate...it allows you to bounce the flash. Off of the ceiling, a wall, a reflector...or even just someone standing there. Bouncing the light will enlarge the light source (soften the light) and change the direction at which it's hitting the subject.

Other advantages are flash power and battery power. It's much more powerful than the built-in...and it has it's own batteries, so it won't drain the camera's battery.